One-time-programmable (OTP) memories are often implemented in integrated circuits and used to store program code and other information. Among other benefits, OTP memories prevent authorized program code from being modified or overwritten with unauthorized program code. Additionally, OTP memories may be programmed by an end user of the integrated circuit through the application of an externally generated programming voltage to the OTP memory. OTP memories are commonly formed of anti-fuse or floating gate non-volatile memory technologies. In order to program the memory cells of the OTP memory, a programming voltage having a voltage level that is higher than the normal operating voltage of the integrated circuit must be applied to the OTP memory cells.
The voltage level required to program an on-chip OTP memory is higher than the operating voltage of the other internal circuitry of the integrated circuit. Exposing the internal circuitry to the higher OTP programming voltage that is required to program the on-chip OTP memory would result in damage to the integrated circuit. As such, it is known in the art to include substantial additional internal circuitry within the integrated circuit that is responsible for the programming of the OTP memory. However, this additional internal circuitry requires the use of more area within the integrated circuit, which is undesirable. Alternatively, an additional programming pin may be provided on the integrated circuit that can be used to provide the higher programming voltage level to the OTP memory during programming. However, such an implementation requires that an extra programming pin be implemented on the integrated circuit. This implementation is undesirable because it increases the cost of the device and limits the backward pin-out compatibility of the integrated circuit.
Accordingly, what is needed in the art is an improved system and method for programming an on-chip OTP memory that does not require substantial additional internal circuitry or additional pins on the integrated circuit.